Spring MVC,绑定默认数据

数据绑定的本质,是将客户端的数据传递给后台,后台将处理结果传递回去。本文介绍默认数据绑定的实现。

常用的默认参数类型如下:

  • HttpServletRequest,通过request对象获取请求信息
  • HttpServletResponse,通过response处理响应信息
  • HttpSession,通过session对象得到session中存储的对象
  • Model/ModelMap,Model是一个接口,ModelMap是一个接口实现,作用是将model数据填充到request域

一、导入Spring MVC所需Jar包,以及Spring AOP包

参考:Spring MVC入门,以及:Spring MVC,基于注解的Spring MVC应用

二、在Web.xml中,配置Spring MVC的前端控制器,包括配置编码过滤器

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xmlns="http://java.sun.com/xml/ns/javaee"
          xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
          http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <servlet>
        <!-- 配置前端过滤器 -->
        <servlet-name>springmvc</servlet-name>
        <servlet-class>
              org.springframework.web.servlet.DispatcherServlet
         </servlet-class>
        <!-- 初始化时加载配置文件 -->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc-config.xml</param-value>
        </init-param>
        <!-- 表示容器在启动时立即加载Servlet -->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    
      <!-- 配置编码过滤器 -->
    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>        
        <filter-class>
               org.springframework.web.filter.CharacterEncodingFilter
        </filter-class>
        <init-param>
            <param-name>encoding</param-name>
               <param-value>UTF-8</param-value>
        </init-param>
    </filter>
    <filter-mapping>
           <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>    
</web-app>

前段控制器的解读,参考:Spring MVC入门;编码过滤器的作用,是解决前后端数据传递的中文乱码问题,即所有的请求信息内容都会以UTF-8的编码格式进行解析。

三、配置springmvc-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
       http://www.springframework.org/schema/context 
  http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    <!-- 指定需要扫描的包 -->
    <context:component-scan base-package="com.itheima.controller" />
    <!-- 定义视图解析器 -->
    <bean id="viewResolver" class=
    "org.springframework.web.servlet.view.InternalResourceViewResolver">
         <!-- 设置前缀 -->
         <property name="prefix" value="/WEB-INF/jsp/" />
         <!-- 设置后缀 -->
         <property name="suffix" value=".jsp" />
    </bean>
</beans>  

对于它的解读,参考:Spring MVC,基于注解的Spring MVC应用

四、创建控制器 

package com.itheima.controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
@RequestMapping(value = "/hello")
public class DefalutParamController {
    @RequestMapping("/defaultParameter")
    public ModelAndView defaultParameter(HttpServletRequest request, HttpServletResponse response, HttpSession session,
            Model model, ModelMap modelMap) throws Exception {
        // 加入读取前台参数的代码
        String inputParam = request.getParameter("name");
        
        // 回传参数到前台 
        request.setAttribute("requestParameter", "您的输入是" + inputParam);
        session.setAttribute("sessionParameter", "这是session参数");
        
        // ModelMap是Model接口的一个实现类,作用是将Model数据填充到request域
        // 即便使用Model接口,其内部绑定还是由ModelMap来实现
        model.addAttribute("modelParameter", "这是model参数");
        modelMap.addAttribute("modelMapParameter", "这是modelMap参数");

        ModelAndView mv = new ModelAndView();
        mv.setViewName("success");
        return mv;
    }
}

 对于它的解读,参考:Spring MVC,基于注解的Spring MVC应用

五、在WEB-INF/jsp目录下,新建success.jsp

内容如下:

<%@ page language="java" contentType="text/html; charset=UTF-8"
     pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
     "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>数据绑定</title>
</head>
<body>
    request: ${requestParameter}
<br/>
    session:${sessionParameter}
<br/>
    model:${modelParameter}
<br/>
    modelMap:${modelMapParameter}
</body>
</html> 

六、启动项目,测试

打开网页:http://localhost:8080/ssm/hello/defaultParameter?name=张三

 

 

posted @ 2021-09-30 11:51  那些年的事儿  阅读(212)  评论(0编辑  收藏  举报